Control mechanism



Feb. 5, 1952 F. H. OWENS CONTROL MECHANISM 2 SHEETS-SHEET 1 Filed May13, 1948 elllllllll HII III! I Farr/7,9 Uk/f/l/S Arraewa s Feb. 5, 1952F. HJOWENS 2,584,734

CONTROL MECHANISM Filed May 13, 1948 2 SHEETS- SHEET 2 Patented Feb. 5,1952 oon'ritol, MECHANISM Freeman aromas, NwYo't-k', Y.

Application Meyia 194s, Sofia-1N0. 26,735 21 Claims! (01. 242-757 I Thepresent invention re ake ajentroi mechanism, and more particmar'iy to aswitch and electrical control mechanism particularly" adapted for usewith apparatus having an elongated medium which iscafried on spools andis reeled from one spool to another;

This application is a continuation-in-part of my application, Serial NO.655,965, of March 21,- 1946, entitled Magnetic Tape Recording andReproducing Apparatusf" new Patent No. 2,513,423 dated, July 4, 1950,and other c'oi'i'struction' details of some of the apparatus herein.disclosed are shown in my copeiiding application, Serial No. 19,683,med Aprils, I948, entitied' Magazine Having Spool aeration Inhibiting-Means. 7 I I While the invention is herein di'sclosed as ap plied to amagnetic tape recording and reproducing' apparatus, the invention itselfis of far broader application, being useable with other types ofreproducing apparatus, with motion pic'- ture projecting machines orcameras, or with any other apparatus in which an elongated medium iswound or unwound, and is" particularly adaptable for use with suchapparatus in which the elongated medium is carried in a" magazine whichis removable from and replace able on the apparatus itself.

In all such devices it is from a practical point of view necessary thatthe" operator" thereof be apprised when the winding or unwinding of theelongated medium is completed or nearly completed in order that" he mayguide himself with regard to the operation being carried out, whether itbe recording, reproducing, photo graphing, or the like. It is alsonecessary in most applications that some means he provided forautomatically terminating the winding or onwinding of the elongatedmedium at a point prior to the time when the medium has been" completelywound or unwound so that rethread= ing of the medium on the spool fromwhich it is unwound is not rendered necessary. This is particularlyimportant when the elongated medium is contained within a replaceablemagazine;

since one of the main advantages'o'f the magazine is that it provides aconvenient means for manipulating the medium without having to handle itdirectly. I

In apparatus of the type describedwhere" a magazine is employed it isalso desirable that means be provided for positively preventinginitiation of the winding or unwinding operation until the magazine isproperly positioned ontlie apparatus; Failure to fulfill thisrequirement Various expedients have in the past been employed aimed ataccomplishing these results but they have all suffered from the drawbackof relative complexity, which in turn gives' rise to the disadvantage ofexpensiveness and undependability. Moreover, where two spools have been;employed, the elongated medium being wound upon one spool as it isunwound from the other, the operation of the apparatus being; reversibl'e so that eachrsp'ool will, at sometime in the operation of theapparatus, be the take-up spool, it has in the past been found necessaryto employ duplicate control means, one associated with each spool, andto employ in addition a relatively complicated interconnecting system soas to render first one and'then the other control means operativedepending upon which spool is the take-up spool. It is also usual insuch prior art mechanism that the control is eiiecfte'd' from thetake-up spool, so that resetting of the control means is made necessaryif an additional amount of elongated medium is eniployed.

It is the prime object of the present invention to devise a controlmeans of the type above described which in the main avoids thedisadvantages set forth.

Another Object or the present invention is to devise a control meanswhich is active upon the supply spool, the control means being actuatedwhen the amount of medium on the supply spool reaches a predeterminedminimum, the, control means being thereby rendered eiT'ective no matter'what the total amount of elongated medium employed.

A more specific object of the present invention is to devise a controlmeans which is not only effective to terminate unwinding of theelongated medium when it is substantially completely unwound from itsspool but which is also effective to energize one or more Warningcircuits at predetermined intervals prior to the time of cessation ofunwindingso as to warn the operator that the tra'nsducing cycle isdrawing to a close.

Yet another object of the present invention is to devise a control meansfor use with a pair of spools between which the elongated medium isadapted to be wound and unwound, said control means including a singleconta'ct carrier ac- 'tive" upon" either of the $1 6015, thus enminatingthe necessity for a separate contact carrier for each spool. A morespecific object is to so construct the control means that the contactcarrier is always caused to engage the spool having the least elongatedmedium thereon, so that said single contact carrier is always controlledby the amount of medium on the supply spool and hence operatesindependently of the total amount of elongated medium employed.

Yet another object is to devise an apparatus upon which a magazine isadapted to be removably placed, the apparatus containing the contactcarrier and all of the necessary electrical connections, said carrierbeing engageable with the medium within the magazine.

Another embodiment of my invention has as its object the devising of amagazine having the control means contained therein, electricalconnection between said control means and the remainder of the apparatusbeing effected when i the magazine is placed in proper position on theapparatus.

Yet another object of the present invention is to so construct anelectrical circuit for the apparatus that it can be completed only whenthe magazine is locked in proper position on the apparatus, thuspositively preventing energization of the apparatus or of a givenelement thereof when the magazine is not properly positioned.

To the accomplishment of the foregoing objects and such other objects asmay hereinafter appear, the present invention relates to theconstruction of apparatus and magazine, and more particularly to theconstruction of control mechanism therein, as defined in the appendedclaims and as set forth in this specification, taken together with theaccompanying drawings, in which:

Fig. 1 is a top view, partially broken away, of one embodiment of myinvention;

Fig. 2 is a schematic diagram of the control and warning circuitsemployed therein;

Fig. 3 is a top View, partially broken away, of a second embodiment ofthe present invention;

Fig. 4 is a view taken along the line 4-4 of Fig. 3;

Fig. 5 is a view taken along the line 55 of Fig. 3;

Fig. 6 is a fragmentary view of a portion of the apparatus of Fig. 3;and

Fig. 7 is a circuit diagram illustrating the electrical connectionsemployed in the embodiment of Figs. 3 through 6.

Generically described, my invention resides in a control mechanismparticularly adapted for use with apparatus generally designated A' uponwhich a magazine generally designated B is removably placeable, themagazine containing an elongated medium C here illustrated as a magnetictransducing tape but which may take a variety of other forms, the mediumC being wound upon and between spools D and D rotatably mounted withinthe magazine B.

A switch generally designated E is provided which acts as the controlmechanism, the switch comprising a contact carrier F bearing a singlecontact and spring urged toward one of the spools D, D, and preferablytoward that spool D or D which has the least of the elongated medium Cthereon, and one or more switch arms G preferably carrying a pluralityof contacts with which the single contact on the contact carrier F isadapted to make successive electrical connection as the supply ofelongated medium on the spool D becomes depleted, thereby energizing aplurality of warning and actuating circuits generally designated H.

In addition, a portion I of an electrical circuit of the apparatus is,in one embodiment, located within the magazine, said interruptedelectrical circuit I being adapted to be closed or completed by alocking pin J outside the magazine B when the magazine is in properposition on the apparatus A, the locking pin J thus serving the dualfunction of fixing the magazine B in proper position on the apparatus Aand closing or completing the circuit I so that an appropriate part ofthe apparatus A may be energized.

The embodiment of Fig. l discloses a magnetic tape recording andreproducing apparatus described in greater detail in my aforementionedapplication, Serial No. 655,965 of March 21, 1945. Insofar as thepresent invention is concerned, it need only be explained that theapparatus A comprises a framework 2 upon which is mounted a drivingroller 4 around which the elongated medium C is adapted to pass and beacted upon by a magnetizing means 6 which, through suitable electricalapparatus (not shown) will serve to record upon and reproduce from themagnetizable tape C. The tape C is contained within the magazine B andis wound upon the spools D and D to form a continuous path between saidspools via magazine rollers 8, l0 and II. The magazine B is adapted tobe placed in proper position upon the apparatus A by motion in adirection into the paper in Fig. 1, one or more upwardly projecting pinsl4 fitting into appropriately located apertures IS in the magazine B soas to properly fix the same in position. One end of the magazine is cutaway as at I8 and the tape C therein is adapted to be grasped throughthe cut away portion l8 and threaded over the driving roller 4 andinside the guide rollers 20 and 22. A motor (not shown) is appropriatelyconnected to the driving roller 4 so as to drive the same and is alsoconnectable to whichever of the spools D or D is to serve as the take-upspool for driving it in rotation.

Mounted in the apparatus A are a pair of solenoids 24 and 26 each havingan armature 28 which is connected by means of a pivotal linkagegenerally designated 30 to a bar 32 which controls appropriate switchingmechanism which may be effective to deenergize the motor so as toterminate its driving operation, to reverse the direction of rotation ofthe motor, to shift the position of the magnetizing means 6, or toperform any other function desired. In addition, the apparatus may beprovided with one or more warning lights such as the yellow light 34 andthe red light 36.

Mounted in the apparatus A below the position which the magazine B willassume is a pivotally mounted arm 38 which is provided with an upwardlyprojecting roller 40 adapted to be received through a suitable aperturein the bottom of the magazine B and to project into the magazine Bbetween the two spools D and D a suflicient distance so that the roller40 is engageable with the elongated medium C on the spools D and D. Anovercenter spring 42 is anchored at one end 44 to the framework 2 and issecured at its other end to the arm 38, the spring 42 being active toconstantly urge the roller 40 into engagement with the medium C on thespool D or D having the least medium thereon. As illustrated in Fig. 1,the spool D has considerably less medium thereon than the spool D andthe roller 40 is in engagement with the medium on the spool D. If thespool Dwere'madethetake upspooland if the apparatus 'A wereenergized;the spoolD would rotate in a clockwise direction soas to accumulate moremedium thereon .while the spool D, rotating in the same direction, wouldprogressively lose its medium and. hence its effective diameter wouldbecome smaller. The roller will ride on the medium C as it accumulateson the spool D until thearm 38 is pivoted past its'center position, atwhichtime the spring will snap it over into engagement/with the mediumon" the spool D, that spool then'havingless medium-onitthan the spoolD.- I s The free'endlli of the'arm' 38 carriesasingle electrical contact48 which is adapted to make successive electrical connection'with theplurality of contacts 58, 52 and 54-on the switcharm G corresponding tothe spool D toward which the roller 48 is urged. As illustrated,'twoswitch arms G are disclosed, each ofwhich is 'in the form of an arm 56pivotally mounted on the framework 2 and-spring urged toward one a'nother by the spring 58. Suitable stops 80 limit the pivotal motion ofthe arms 56 toward one another.

When the arm 381s first urged toward one or the other of the spools D orD, the contact 48 will be held out of electrical connection with any ofthe contacts '50, 52 or 54. As the amount of medium C on the spoolthereafter becomes-depleted, the arm 38will move so that the contact 48carried thereby will'make successive electrical connection with thecontacts 50, 52and 54. -As' the amount of medium C on the spool D, forex ample, becomes depleted, the contact 48 willslide across the innerface 82 of-the arm 56 and will ultimately make electrical connectionwith the contact 58, the uppermost contact thereon, this leading toillumination of, for example, -the'ye1- low light 34, thus indicating tothe operator that minutes of operating time'remains before thespool Dwill be substantially completely unwound. As,0perati0n of the mechanismcontinues and hence as the amount of the medium C on the spool D becomesfurther depleted, the contact 48 will make electrical connection withthe middle contact 52 on the switcharm G, which may lead to illuminationof the redlight as, indicating to' the operator that only one minute. oftime re mains; As the amount ofmedium C on the spool D becomes furtherdepleted; electrical conneca' tion will be made betweenthecontact 4'8and the lowermost contact 54 on the switch arm G'which,

as illustrated, may energize the solenoid 24' was to stop the motor,reverse it, or performanyother' desired function.

The advantages of the embodiment of Fig. 1

as compared with the embodimentof 3"'i s, that the magazine structure inFig. 'lis'of ex treme simplicity, including only the magazine casing64-and the spools Band D, all 'of'the corrtrol mechanism beingpermanently a part ofthe thespools-D or D. I v a Theapparatusillustratedin Figs; 3 through 7 eliminates this diihculty because-thecontrol mechanism is largely a part of the magazineB itself;- While)thisovercomes the manipulative drawbacksdescribedmbov'e, it makes themega not herein disclosed are. described in my'copend-- ing application,Serial No. 26,736, flled'May 13,.

1948, entitled Driving and Looking Means'for Apparatus Having RemovableMagazine. Insofar as the present invention is concerned, the

apparatus A includes a wall'BB over which the magazine B is adapted tobeslid to properposl-gtion, a projecting lug 68 on the apparatus A' 921-tering aslot 10 in the recessed front-wall 12 01 the magazine to limitthesliding motion-thereof. When the magazine B is in proper. position,--a driving wheel 4 engages the magnetizing me-. dium" C so as to drivethesame while amasnetizing means 6', two of which are shown, eachadapted to be used in alternation with the other; cooperates with thetape C so as to record thereon or reproduce therefrom. Thetape C'passeswithin the magazine from spool D to spool D rollers 8 and 10.

The magazine B is provided witha bottom wallv l4 adapted to slide overthe wall 66 of the apparatus A, with a central frame member 16 abovewhich-the spools D and D are mounted, and with atop wall 18. form=of afiat arm 38' mounted on the underside of the central frame member 16 soas to pivot about pin 80. The roller 40 projects up through an arcuateslot 82 in the central framemember 76 so as to be engageable with themedium C on either of the spools-Der D. 84 is freely pivotally mountedon the underside of thearm 38 by means of rivet 86, the depending armsof the bracket receiving therethrough the narrowed end 88 of the arm 98which is pivotally mounted aboutstud'92. A spring '84 is maintained incompression between the bracket 84 andthe widened portion ofthe arm 90,th'e spring'94'thus acting as an overcenterspring so as to always urgethe arm 38' in a direction such that the roller 48' makes engagementwith the *D which has the the arm Hill is visible through a window I06in the top wall 18, the arm I being provided with an index line I!!! foraccurate indications; 'A' marking pad H2 may be secured to the top wall18 of the magazine B adjacent the window I06 so that marks may be madethereon for future reference corresponding to any data desired'such asthe'position on the medium C of particularrecorded intelligence.

The arm 38 and the switch arm G may besim'i larly constructed andarranged to those illustrated in Fig. 1 except thatthey will becontained within the magazine B rather than beingmounted on theapparatus A. An alternative construction:

is, specifically disclosed in Figs. .3, .4 and 5 in which the switcharms Gare defined by arms 56 each carrying: contacts 58 52" and 54"whichj'are disposed p'erpendicular--tothepl'ane or motion 0% via guideThe contact carrier F is in the A U-shaped bracket the contact carrier38 rather than parallel thereto as was the case in Fig. 1. In addition,the spring 58 is active between opposing portions I I 4 on the arms 58themselves, and an arcuate positive stop 60' extends between the arms56' to limit their inward motion. The arm 38, in the embodiment herespecifically illustrated, may it self be conductive. The contact carrier36 carries a contact 48 adapted, as the amount of medium C on the spoolsD or D toward which the contact carrier .38 is urged becomes depleted,to make successive electrical connection with the contacts 50, 52' and54 on the appropriate switch arm G, thus, as in the previous embodiment,energizing a plurality of warning and actuating circuits.

The contacts 50', 52 and 54' are each connected, by means of the cablesH6 and H6, to conductive pins I20, I22 and I24 respectively, there beingtwo sets of these pins, each being connected to the contacts on one ofthe switch arms G and each set projecting out through the sides of themagazine B so as to make electrical connection with contacts I26, I28and I30 respectively on the apparatus A, the positioning of the contactsI26, I28 and H being such that electrical connection is made only afterthe magazine B has been slid to proper position.

Electrical connection to the contact 48 carried by the contact carrier38 is made via a contact pin I32 in the magazine B and a correspondingcontact I34 on the apparatus A, these two pairs of contacts being hereillustrated adjacent to the upper set of contacts I through I in Fig. 3.The circuit between the contact I32 in the magazine B and the contact 48carried by the contact carrier 38' is defined by a pair of wires I36 andI38 (see Fig. 7) these two Wires terminating at separated points I40 andI42 (see Figs. 4 and '7), these points being located just above thebottom wall "I4 of the magazine B and on either side of an aperture I44therein. The locking pin J which is movably mounted on the apparatus Ain a manner hereinafter to be described is receivable within theaperture I44 when the magazine B is in proper position on the apparatus,the pin thus locking the magazine B in its proper position and also,since it is formed of conductive material, bridging the gap between thepoints I40 and I42 so as to complete the circuit to the contact 48'. Acircuit is also completed through wire I46 to contact I43 in themagazine B, said contact I48 being adapted to make electrical connectionwith the contact I50 on the apparatus A and thence, via wire I52, to thedriving motor M of the apparatus. By virtue of this method ofconnection, it will be apparent that neither the motor M nor any of thewarning or actuating circuits H can be energized until the magazine B isin proper position on the apparatus A, since it is only at that timethat the contacts I20, I22, I24, I32 and I48 in the magazine B makeelectrical connection with the corresponding contacts I26, I28, I30, I34and I50 on the apparatus A, and that in addition neither the motor M northe warning and actuating circuits H can be energized until the magazineB is locked in its proper position by entry of the locking pin J intothe aperture I44 of the magazine B, since it is only at that time thatelectrical connection is bridged between the points I40 and I42.

The locking pin J, together with the driving means I54 and I54engageable with each of the spools D and D, are mounted on plate I56which is, by virtue of pin and slot connections I68 and I66, verticallymovable to a limited degree on the side of the apparatus A, manualmanipulation thereof being facilitated by operating knob I6I. When theplate I56 is moved downward, both the locking pin J and the drivingmeans I54 and I54 are housed within recess I62 in the wall 66 of theapparatus A so as not to interfere with the sliding movement of themagazine B to and from its proper position. When the plate I56 is movedupwardly, the driving means I54 and I54 are moved upwardly into drivingengagement with the spools D and D respectively and the locking pin J ismoved upwardly into the aperture I44 in the magazine B for the purposesabove described.

The functioning of the control mechanisms of the present invention willin the main be fully apparent from the above description. Insofar as theswitch itself is concerned, the contact carrier 36 is spring urged intoengagement with the medium C and as the medium C changes its position,the contact 48 carried by the carrier 38 comes into successiveengagement with a plurality of contacts 50, 52 and 54 carried by aswitch arm G, thus energizing a plurality of warning and actuatingcircuits. In the specific modification here disclosed, the carrier 38 iseffective on both spools D and D, an overcenter spring 42 or 94 beingprovided so as to constantly urge it into engagement with the medium Con the spool D or D having the least medium C thereon. When the carrier38 is first urged into engagement with a given spool, its contact 48makes no electrical connection, but as the medium C on the spool becomesdepleted, the contact 48 moves over the face of the switch arm G,passing from contact 50 to contact 52 to contact 54 successively, thecontact 50 energizing a yellow light 34, the contact 52 energizing astop light 36, and the contact 54 energizing a stopping or reversingmechanism as here disclosed. It will be understood that the warnings maybe audible as well as visual. The switch mechanism involved is simple,with a minimum number of moving parts. It is exceedingly effective,particularly when two spools D and D' are employed between which themedium C is adapted to be wound and unwound. In such a case, only asingle contact carrier 38 is required, thus reducing the complexity andexpense of prior art devices in which each spool required its owncomplete switching mechanism. Another important factor is that eventhough only a single contact carrier 38 is employed, that carrierfunctions independently of the total amount of medium C in the magazineB, since it works only on the spool D having the least medium thereon.

The embodiment of Fig. 1 has the advantage that all of the controlmechanism is included in the apparatus A, so that the magazine B may beof exceedingly simple and consequently inexpensive construction. Thefirst embodiment is, however, subject to the disadvantage thatmanipulation is sometimes required to ensure that the roller 40 on thecarrier 38 fits between the spools D and D as the magazine B is placedin position. This disadvantage is eliminated in the embodiment of Figs.3 through 7 by incorporating the switch mechanism in the magazine Bitself. This, however. has the drawback of increasing the cost of eachmagazine B. However, certain operational advantages are thought toovercome this drawback, these advantages being that, by virtue of theplacement of the contacts I20, I22, I24, I32 and I48 in the magazine B.and the corresponding placement of the contacts I26, I28, I30, I34 andI50 upon the apparatus A, electrical connection between the contacts isonly made when the magazine B is in proper position on the apparatus A,thus adding a definite safety factor to the functioning of themechanism.

In addition, means including the, locking pin J are provided forensuring that none of the apparatus, not even the motor M, can beenergized until the magazine B is securely locked in its properposition. Since the warning and azine B with contact I50 on theapparatus A is positively prevented.

While only two embodiments of my invention are here illustrated, both inconjunction with magnetic tape reproducing apparatus, it will be clearthat many variations may be made in the details of the controlmechanisms of my invention and that my invention may be employed withmany types of apparatus, all within the spirit thereof as defined in theappended claims.

I claim:

1. In a switch controlled by the position of a medium, a support, acontact carrier mounted in said support and spring urged into, engage.-ment with said medium and bearing an electrical contact, a switch armpivotally mounted in said support and resiliently urged toward saidcarrier and bearing a plurality of electrical contacts with which saidcontact on said carrier is adapted to make successive electricalconnection, said switch arm moving with said contact carrier as thelatter moves in response to theposition of said medium, and a pluralityof circuits each connected to one of said plurality of contacts andsuccessively energized as the position of said medium changes.

2. In an apparatus in which an elongated medium is carried on spools andis reeled from one spool to another, a switch controlled by theunwinding of said medium from said spools comprising a support, acontact carrier mounted on said support and sprin urged into contactwith the medium on the spool having the, least of said 1 medium thereonand bearing an electrical contact, and a pair of cooperating switcharms, one for each spool, each mounted on the support and bearing aplurality of electrical contacts with which said contact on said carriermakes successive electrical connection as the amount of medium on thespool corresponding to the cooperating switch arm with which saidcarrier is in contact becomes depleted, thereby successively energizinga plurality of circuits.

3. In an apparatus in which an elongated medium is carried on spools andis reeled from one spool to another, a switch controlled by theunwinding of said medium from said spools comprising a support, acontact carrier mounted on said support and spring urged into contactwith the medium on the spool having the least of said medium thereon andbearing an electrical contact, and a pair of cooperating switch arms,one for each spool, each mounted on the support and resiliently urgedtoward said first switch arm and each bearing a plurality of electricalcon.- tacts with which said contact on said carrier makes successiveelectrical connection as the amount of medium on the spool correspondingto the cooperatingswitch arm with which said carrier is incontactbecomes depleted, thereby successively energizing a plurality ofcircuits,

4. In a recording and reproducing apparatus in which an elongatedtransducing medium is employed, a switch controlled by the amount ofmedium in said apparatus comprising a contact carrier mounted on saidapparatus and spring urged into engagement with said medium and bearinga single electrical contact, and a switch arm pivotally mounted on saidapparatus and resiliently urged toward said carrier and bearing .aplurality of electrical contacts with which said single contact on saidcarrier makes successive electrical connection as the amount of mediumin said apparatus becomes depleted, said switch arm moving with saidcontact carrier as the latter moves in response to the amount of mediumin said apparatus, thereby successively actuating a plurality of warningand actuating circuits.

5. In a recording andv reproducing apparatus in which an elongatedtransducing medium is employed, spools rotatable in said apparatus onwhich said medium is carried, and a switch controlled by the unwindingof said, medium from said spools comprising a contact carrier mounted onsaid apparatus and spring urged into engagement with the medium on thespool having the least medium thereon and bearing a single electricalcontact, and a pair of cooperating switch arms, one for each spool, eachmounted on the apparatus and bearing a plurality of electrical contactswith which said single contact on said carrier makes successiveelectrical connection as the amount of medium on the spool correspondingto the switch arm with which said carrier is in contact becomes.depleted, thereby successively energizing a plurality of warning andactuating circuits.

6. In a recording and reproducing apparatus in whichan elongatedtransducing medium is employed, spools rotatable in said apparatus onwhich said medium is carried, a switch means controlled by the unwindingof the medium from said spools comprising a contact carrier bearing asingle electrical contact pivotally mounted so as to engage the mediumon either spool, an overcenter spring active on said carrier to urge itinto contact with the medium on the spool having the least mediumthereon, and a pairof cooperating switch arms, one for each spool, eachmounted on the apparatus and bearing a plurality of electrical contactswith which said single contact on said carrier makes successiveelectrical connection as the amount of medium on the spool correspondingto the switch arm with which said carrier is in contact becomesdepleted, thereby successively energizing a plurality of warning andactuating circuits.

7. In combination, an apparatus cooperable with an elongated medium anda magazine removable from said apparatus comprising a casing and a spoolon which said medium is carried and from which it is adapted to be woundand 1m,-

wound, said apparatus comprising a contact carrier and a cooperableswitch arm, said magazine casing being elongatedly apertured, saidcontact carrier havin a member receivable through said aperture andengageable with the medium on said spool, and a spring active on saidcarrier to urge said member into constant engagement with said medium,the contacts on said carrier and said switch arm making electricalconnection to energize a suitable circuit as the amount of medium .1 onsaid spool becomes depleted.

8. In combination, an apparatus cooperable with an elongated medium anda magazine removable irom said apparatus comprising a casing and a spoolon which said medium is carried and from which it is adapted to be woundand unwound, said apparatus comprising a contact carrier bearing anelectrical contact and a cooperable switch arm bearing a plurality ofelectrical contacts, said magazine casing being elongatedly apertured,said contact carrier having a member receivable through said apertureand engageable with the medium on said spool, and a spring on saidapparatus active on said carrier to urge said member into constantengagement with said medium, said carrier contact making successiveelectrical connection with the plurality of contacts on said switch armas the amount of medium on said spool becomes depleted, therebysuccessively energizin a plurality of warning and actuating circuits.

9. In combination, an apparatus cooperable with an elongated medium anda magazine removable from said apparatus comprising a casing and a pairof spools on which said medium is carried and from and between which itis adapted to be wound and unwound, said apparatus comprising a contactcarrier bearing an electrical contact, and a pair of cooperable switcharms, one for each spool, each bearing a second electrical contact, saidmagazine casing being elongatedly apertured, said carrier having amember receivable through said aperture and engageable with the mediumon said spools, and an overcenter spring active on said carrier to urgesaid member into engagement with the medium on the spool having theleast medium thereon, said carrier contact making electrical connectionwith the contact on the switch arm corresponding to the spool with whichsaid member is in engagement so as to energize a suitable circuit as theamount of medium on said spool becomes depleted.

10. In combination, an apparatus cooperable with an elongated medium anda magazine removable from said apparatus comprising a casing and a pairof spools on which said medium is carried and from and between which itis adapted to be wound and unwound, said apparatus comprising a contactcarrier bearing an electrical contact, and a pair of cooperable switcharms, one for each spool, each bearing a plurality of electricalcontacts, said magazine casing being elongatedly apertured, said carrierhaving a member receivable through said aperture and engageable with themedium On either of said spools, and an overcenter spring active on saidcarrier to urge said member into engagement with the medium on the spoolhaving the least medium thereon, said carrier contact making successiveelectrical connection with the plurality of contacts on the cooperableswitch arm corresponding to the spool with which said member is inengagement as the medium on said spool becomes depleted, therebysuccessively energizing a plurality of warning and actuating circuits.

11. In combination, an apparatus cooperable with an elongated medium anda magazine removable from said apparatus comprising a casng and a pairof spools on which said medium is carried and from and between which itis adapted to be wound and unwound, said apparatus comprising a contactcarrier bearing an electrical contact, and a pair of cooperatin switcharms, one for each spool each bearing a plurality of electrical contactson one face thereof, pivotally mounted and resiliently urged to;

ward one another to a limited degree, said carrier bein movable betweensaid cooperating switch arms, said magazine casing being elongatedlyapertured, said carrier having a member receivable through said apertureand engageable with the medium on either of said spools, and anovercenter spring active on said carrier to urge said member intoengagement with the medium on the spool having the least medium thereon,said carrier contact sliding over the contact-bearing face of the switcharm corresponding to the spool with which said member is in engagementand making successive electrical connection with the plurality ofcontacts carried by said cooperable switch arm as .the medium on saidspool becomes depleted, thereby successively energizing a plurality ofwarning and actuating circuits.

12. A magazine comprising a casing, a spool rotatably mounted thereinupon which an elongated medium is adapted to be wound and unwound, acontact carrier movably mounted therein and resiliently urged intocontact with the medium on said spool and bearing a electrical contact,and a cooperable switch arm pivotally mounted in said magazine andresiliently urged toward said carrier and bearing a plurality ofelectrical contacts, said carrier contact making successive electricalconnection with the plurality of contacts on said switch arm as theamount oi medium on said spool becomes depleted, said switch arm movingwith said contact carrier as the latter moves in response to the amountof medium on said spool thereby successively energizing a plurality ofwarning and actuating citcults.

13. A magazine comprising a casing, 91 pair of spools rotatably mountedtherein on and between which an elongated medium is adapted to wound andunwound, a contact carrier movably mounted therein and resiliently urgedinto con= tact with the medium on the spool having the least mediumthereon, and a pair of cooperable switch arms, one for each spool, eachbearing a plurality of electrical contacts, said carrier con tact makingsuccessive electrical connection with the plurality of contacts on theswitch arm corre-- sponding' to the spool with which said carrier is inengagement as the amount of medium on said spool becomes depleted,thereby successively energizing a plurality of warning and actuatingcircults.

14. A magazine comprising a casing, a pair of spools rotatably mountedtherein on and between which an elongated medium is adapted to be woundand unwound, a contact carrier movably mounted therein and resilientlyurged into contact with the medium on the spool having the least mediumthereon, and a pair of cooperable switch arms, one for each spool, oneon each side of said carrier and resiliently urged theretoward and eachbearing a plurality of electrical contacts, said carrier contact makingsuccessive electrical connection with the plurality of contacts on theswitch arm corresponding to the spool with which said carrier is inengagement as the amount of medium on said spool becomes depleted,thereby successively energizing a plurality of warning and actuatingcircuits.

15. A magazine comprising a casing, a pair 01 spools rotatably mountedtherein on and between which an elongated medium is adapted to be woundand unwound, a contact carrier movably mounted therein so as to engagethe medium on either spool, an overcenter spring active on said carrierto urge t nt? c t ct with. the medium on the spool having the leastmedium thereon, a pair of cooperable switch arms, one for each spool,each bearing a plurality of electrical contacts, said carrier contactmaking successive electrical connection with the plurality of contactson the switch arm corresponding to the spool with which said carrier isin engagement as the amount of medium on said spool becomes depleted,thereby successively energizing a plurality of warning and actuatingcircuits.

16. A magazine comprising a casing, a pair of spools rotatably mountedtherein on and between which an elongated medium is adapted to be woundand unwound, a contact carrier movably mounted therein so as to engagethe medium on either spool, an overcenter spring active on said carrierto urge it into contact with the medium on the spool having the leastmedium thereon, a pair of cooperable switch arms, one for each spool,one on each side 01' said carrier and resiliently urged theretoward andeach bearing a plurality of electrical contacts, said carrier contactmaking successive electrical connection with the plurality of contactson the switch arm corresponding to the spool with which said carrier isin engagement as the amount of medium on said spool becomes depleted,thereby successively energizing a plurality of warning and actuatingcircuits.

17. In combination, an apparatus and a removable magazine comprising acasing having an aperture, an interrupted portion of an electricalcircuit therein, and means for closing said circuit located in saidcasing in a position to be actuated by an element receivable throughsaid aperture, and a locking pin movably mounted on said apparatus andinsertable into said aperture in said magazine only when said magazineis in proper position on said apparatus, said locking pin constitutingsaid element receivable through said aperture.

18. In combination, an apparatus and a removable magazine comprising acasing having an aperture and a portion of an electrical circuit in saidcasing including a pair of separated contacts on either side of saidaperture, said contacts being adapted to make electrical connection withand be bridged by an element receivable through said aperture, and alocking pin movably mounted on said apparatus and insertable into saidaperture in said magazine only when said magazine is in proper positionon said apparatus, said locking pin constituting said element receivablethrough said aperture.

19. In combination, an apparatus and a removable magazine cooperabletherewith and containing a medium to be driven by said apparatus, saidapparatus comprising a driving means, a first portion of an electricalenergizing circuit for said driving means, and a magazine locking pin,and said magazine comprising a casing hav ing an aperture for receivingsaid locking pin, a second portion of said electrical energizing circuitincluding an interrupted portion thereof,

and means for closing said interrupted portion located in said casing ina position to be actuated by said locking pin as it is received in saidaperture, said apparatus and said magazine including cooperable contactsfor making electrical connection between said first and second portionsof said electrical energizing circuit, whereby said driving means cannotbe energized until said magazine is locked in proper position on saidapparatus.

20. In combination, an apparatus and a removable magazine cooperabletherewith and containing a medium to be driven by said apparatus, saidapparatus comprising a driving means, a first portion of an electricalenergizing circuit for said driving means, and a magazine locking pin,and said magazine comprising a casing having an aperture for receivingsaid locking pin, and a second portion of said electrical energizingcircuit including a pair of separated contacts on either side of saidaperture, said contacts being adapted to make electrical connection withand be bridged by said locking pin as it is received in said aperture,and said apparatus and said magazine including cooperable contacts formaking electrical connection between said first and second portions ofsaid electrical energizing circuit, whereby said driving means cannot beenergized until said magazine is locked in proper position on saidapparatus.

21. In combination, an apparatus and a removable magazine cooperabletherewith and containing a medium to be driven by said apparatus, saidapparatus comprising a driving means, a first portion of an electricalenergizing circuit for said driving means, electrical contacts forming aportion of said circuit, and a magazine locking pin, and said magazinecomprising a casing having an aperture for receiving said locking pin, asecond portion of said electrical energizing circuit including separatedcontacts on either side of said aperture, said contacts being adapted tomake electrical connection with and be bridged by said locking pin as itis received in said aperture, and electrical contacts on the exterior ofsaid casing forming a portion of said circuit, said casing contacts andsaid apparatus contacts being so positioned as to make electricalconnection only when the magazine is properly positioned on saidapparatus, whereby said driving means cannot be energized until saidmagazine is in proper position on said apparatus and locked in saidproper position.

FREEMAN H. OWENS.

'- file of this patent:

UNITED STATES PATENTS Number Name Date 1,933,506 Noyes Oct. 31, 19332,096,445 Begun Oct. 19, 1937 2,419,476 Begun Apr. 22, 1947 FOREIGNPATENTS Number Country Date 4,933 Australia Nov. 26, 1926 787,440 FranceJuly 8, 1935

